Animals with antifreeze

Why don’t fish freeze in the Arctic Ocean?

Brrrrr! It's cold outside. Lots of animals are much better
adapted to the cold weather than we are. Polar bears have thick
fur, seals and whales have a layer of blubber and some birds
migrate.

But what if you're a fish?

Birds and mammals are 'warm-blooded'. They can keep their body
temperature higher than the icy environment around them. Fish are
'cold-blooded'. Their body temperature is the same as their
surroundings. In the Arctic and Antarctic Oceans, the temperature
is very chilly - below 0 degrees Celsius. The salt in the oceans
stops them freezing.

Why don't fish freeze?

To stop their blood freezing, some fish that live in the Arctic
and Antarctic have special antifreeze proteins.

Antifreeze proteins are very clever. They slow down the
formation of bonds between water molecules, which prevents the
formation of ice crystals in the fish's blood.

Scientists are working out how they could use these antifreeze
proteins as a non-polluting de-icer for cars and machinery.
Antifreeze proteins could also be used to prevent food freezing and
to preserve delicate organs during organ transplants.